LOCATION SONSELA NM AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Sonsela very cobbly fine sandy loam, extremely bouldery -- forest. The soil surface has a discontinuous cover of leaves, needles, and twigs. (Colors are for dry soil unless otherwise noted. When described, the soil was dry throughout.)
A-- 0 to 4 inches; brown (7.5YR 4/2) very cobbly fine sandy loam, very dark brown (7.5YR 2.5/2) moist; weak thick platy structure parting to moderate medium granular; soft, very friable, slightly sticky and nonplastic; few medium and fine and common very fine roots; few very fine irregularly shaped pores; 30 percent gravel, 15 percent cobbles, 5 percent stones, and 5 percent boulders; neutral (pH 7.0); clear smooth boundary. (2 to 4 inches thick)
BA-- 4 to 9 inches; brown (7.5YR 5/3) gravelly fine sandy loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few medium and common fine and very fine roots; common very fine irregularly shaped pores; 20 percent gravel and 5 percent cobbles; slightly acid (pH 6.4); clear smooth boundary. (0 or 5 inches thick)
Bt1-- 9 to 16 inches; reddish brown (5YR 5/3) very gravelly fine sandy loam, reddish brown (5YR 4/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few coarse to fine and common very fine roots; few fine and very fine tubular pores; few moderately thick clay films on faces of peds and common thin clay films on faces of peds and bridging sand grains; 30 percent gravel and 10 percent cobbles; slightly acid (pH 6.4); gradual smooth boundary. (6 to 17 inches thick)
Bt2-- 16 to 26 inches; reddish brown (5YR 5/4) very gravelly sandy clay loam, reddish brown (5YR 4/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; hard, firm, sticky and plastic; common coarse and few medium to very fine roots; few fine and common very fine tubular pores; few moderately thick clay films on faces of peds and common thin clay films on faces of peds and on rock fragments; 35 percent gravel, 15 percent cobbles, and 5 percent stones; slightly acid (pH 6.4); gradual smooth boundary. (8 to 20 inches thick)
Bt3-- 26 to 48 inches; reddish brown (5YR 5/4) very cobbly sandy clay loam, reddish brown (5YR 4/4) moist; moderate medium prismatic structure parting to weak medium subangular blocky; hard, firm, sticky and plastic; few coarse to very fine roots; few fine and common very fine tubular pores; few moderately thick clay films on faces of peds and common thin clay films on faces of peds and on rock fragments; 30 percent gravel, 20 percent cobbles, and 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (11 to 22 inches thick)
Bt4-- 48 to 70 inches; brown (7.5YR 5/4) extremely cobbly fine sandy loam, reddish brown (5YR 4/4) moist; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few coarse to very fine roots; few fine and common very fine tubular pores; few moderately thick clay films on faces of peds and few thin clay films on faces of peds and on rock fragments; 35 percent gravel, 35 percent cobbles, and 5 percent stones; non-effervescent with some spots very slightly effervescent, secondary calcium carbonates segregated as very few fine rounded accumulations on faces of peds; neutral (pH 6.8).
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 9 miles west-southwest of Sheep Springs; 450 feet north and 200 feet east of the southwest corner of sec. 27, T.22N., R.19W.; Latitude 36 degrees 6 minutes 20 seconds N and Longitude 108 degrees 51 minutes 43 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture: Intermittently moist in all parts of the soil moisture control section from January to May and intermittently moist in some part from June to December. Typic ustic soil moisture regime.
Soil temperature: 41 to 43 degrees F.
Mean summer soil temperature: 59 to 63 degrees F.
Reaction: slightly acid or neutral
Silicate clay content, control section weighted average: 18 to 27 percent
Rock fragment content, control section weighted average: 35 to 60 percent
Organic carbon content: less than 0.6 percent below 9 inches
Depth to base of argillic horizon: 60 inches or more
A horizon
Hue: 5YR, 7.5YR.
Value: 3 or 4 dry, 2 or 3 moist
Organic carbon content: 1.8 to 2.4 percent
Rock fragments: 35 to 60 percent; gravel, cobbles, stones or boulders
BA horizon (when present)
Hue: 5YR, 7.5YR
Value: 4 or 5 dry, 3 or 4 moist
Texture: gravelly fine sandy loam or gravelly loam
Organic carbon content: .6 to 1.2 percent
Rock fragments: Total range is 15 to 35 percent; 10 to 20 percent pebbles; 5 to 10 percent cobbles; 0 to 5 percent stones
Bt horizons
Hue: 5YR, 7.5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Texture: fine sandy loam, sandy loam, loam, sandy clay loam with appropriate modifiers
Clay content: 18 to 27 percent
Rock fragments: 35 to 80 percent gravel, cobbles, stones, or boulders
Other features: some pedons contain very few calcium carbonate accumulations, and have up to 2 percent calcium carbonate equivalent.
COMPETING SERIES: These are the Colomex (NM), Laventana (NM), Macmeal (MT), Mocmont (MT), Namon (UT), Sheek (CO), Skyview (MT), Tecolote (CO), Towaoc (CO), Trapps (MT), Vision (MT), Wahatoya (CO), Xankey (NM), Ymark (MT), Yourame (MT), and Yreka (MT) series. Ymark soils are deep. Macmeal, Trapps, and Yourame soils have accumulations of calcium carbonate. Colomex soils formed in stratified alluvium and have an abrupt change to sandy textures within 40 inches. Laventana soils have albic horizons. Mocmont soils have glossic horizons. Namon soils are deep to a lithic contact of sandstone. Sheek soils are slightly drier and have soil temperatures of 44 to 47 degrees F. Skyview and Wahatoya soils are moderately deep. Tecolote soils have an albic horizon. Towaoc soils have less than 18 percent clay. Xankey soils have lithologic discontinuities of loamy material between 24 and 40 inches and soil temperatures of 44 to 47 degrees F. Yreka soils have mixed E/Bt horizons. In addition, Macmeal, Mocmont, Skyview, Trapps, Vision, Wahatoya, Ymark, Yourame, and Yreka soils are moist in the soil moisture control section during May and June and occur in the Great Basin. Vision soils have less than 35 percent rock fragments in the upper part of the particle-size control section.
GEOGRAPHIC SETTING: Sonsela soils are on backslopes of hills, buttes, and escarpments. They formed in colluvium derived from Tertiary basalt and tuff-breccia. Slopes are 35 to 70 percent. Elevation ranges from 8,200 to 9,800 feet. The mean annual precipitation is 18 to 24 inches with more than 50 percent falling as snow from winter storms. The mean annual temperature is 39 to 43 degrees F. The average frost-free period is 60 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Owlspring, Todacheene, Viewpoint, and Washpass soils. Owlspring soils are fine-silty, somewhat poorly drained, and occur on toeslopes. Todacheene soils are fine-loamy, have mollic epipedons, and occur on footslopes and fan terraces. Viewpoint soils are shallow, have mollic epipedons, and occur on adjacent shoulders. Washpass soils are coarse-loamy, have a cryic temperature regime, and occur on adjacent north-facing backslopes.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderate permeability
USE AND VEGETATION: Sonsela soils are used for timber production and livestock grazing. Present vegetation is ponderosa pine, Douglas fir, and scattered Rocky Mountain juniper and pinyon; with an understory of muttongrass, bottlebrush squirreltail, earth sedge, nodding bromegrass, Arizona fescue, mountain snowberry, Oregongrape, and Gambel oak.
DISTRIBUTION AND EXTENT: Sonsela soils occur in northwest New Mexico and northeast Arizona. MLRA 35; LRR-D. Sonsela soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Shiprock Area, Parts of San Juan County, New Mexico and Apache County, Arizona; 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 9 inches (A and BA horizon)
Mollic intergrade - mollic colors are present in the upper 7 inches when mixed
Argillic horizon - The zone from 9 to 70 inches (Bt1, Bt2, Bt3, and Bt4 horizons)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
ADDITIONAL DATA: Organic carbon content determined by Inter-Mountain Laboratories, Inc.
Updated and revised for the correlation of Ft. Defiance Area AZ715 2/08 DWD